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From: David Brown <david.brown@hesbynett.no>
Newsgroups: comp.arch,comp.lang.misc
Subject: Re: In-Memory Computing
Date: Tue, 19 Nov 2024 08:20:55 +0100
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On 18/11/2024 19:09, Michael S wrote:
> On Mon, 18 Nov 2024 15:25:37 -0000 (UTC)
> John Levine <johnl@taugh.com> wrote:
> 
>> According to Lawrence D'Oliveiro  <ldo@nz.invalid>:
>>> On Sun, 17 Nov 2024 21:32:29 +0000, MitchAlsup1 wrote:
>>>   
>>>> ... doing arithmetic in ferrite cores has been around for a very
>>>> long time, indeed.
>>>
>>> Memristors are a new kind of electronic component, where the
>>> resistance is proportional to the integral of applied voltage over
>>> time.
>>
>> This is a rather capacious version of "new" since memristors were
>> invented in 1971.
>>
>> My impression is that they are real, they work, but they don't work
>> well enough to replace conventional components.
>>
>> There is a very long article about them in Wikipedia.
> 
> My impression from Wikipedia article is different. Memristors are not
> real.
> I.e. there are no physical devices that approximate mathematical
> abstraction proposed in 1971. There are some devices taht look like
> that, but only before researcher starts to pay attention to details.
> After researcher starts to pays attention to details it typically turns
> out that device resistance does not really depend on charge, but on
> something else that happens to correlate with charge on bigger or
> smaller parts of characteristic curves.
> 

All electronic devices are approximations.  There is no such thing as a 
pure resistor, or a pure capacitor, or pure inductor.  Current 
memristors are no different in principle, but are - for now, at least - 
poorer approximations than the more common components.  Whether they 
will ever be close enough to be of practical use, remains to be seen.

> What does exist and does work and does not work well enough relatively
> to conventional tech are various variants of ReRAM. But memory elements
> of those various ReRAMs are *not* memristors. That applies as much to
> HP's not quite working "memristor" ReRAM as to all others ReRAMs in
> existence including those that work relatively better.
> 

Yes, that is my understanding too - there are a variety of memory 
devices that have been made with different properties and niches, but I 
don't believe any of them are based on devices that are close enough to 
ideal memristors to justify using the term.